Hungry Jack’s has been fined for underpaying almost 700 staff over $665,000 between March 2006 and August 2008, the Fair Work Ombudsman said.

It also admitted to further breaching workplace laws by failing to keep proper employment records.

The fast food retailer will be forced to pay $100,500 in penalties, which was imposed by federal magistrate Philip Burchardt.

In his judgment, federal magistrate Burchardt described the conduct of Hungry Jack’s as “contravention on a major scale”, saying the total underpayment was “enormous”.

“More than 30 employees were underpaid more than $4000 each and the highest individual underpayment was over $10,000,” he said.

“These underpayments have all been rectified but the fact is that the relevant employees were denied the sums that they were lawfully due at the time they were actually working.”

The underpaid employees worked at six Hungry Jack’s owned-and-operated stores in Devonport, Glenorchy, Hobart, South Hobart, Launceston and Mowbray.